Control and Coordination – Coordination in Plants
* Plants show two different types of movement- One independent of growth and the other dependent on growth.
* Plants growth in the direction of stimulus is defined as tropic movement.
* The movement of a plant part is response to light is called phototropism.
* The movement of a plant part is response to gravity is called geotropism.
* The movement of a plant part is response to chemicals is called chemotropism.
* The movement of a plant part is response to water is called hydrotropism.
* The directional growth movement of a plant part in response to the touch of an object is called thigmotropism.
* Plants have different hormones which help coordinate growth development and response to the environment.
* The nastic response is not a directional movement of the plant part with respect to the stimulus.
* Auxins are plant hormones that promote and regulate the growth and development of plants.
* Gibberellins are plants hormones that help in the elongation of internodes.
* Cytokininis are plants hormones that promote cell division. They also promote the closing of the stomata.
* Abscisic acid is a plant hormone that inhibits growth. Its effects include wilting of leaves.